The Biological Approach: Assumptions

eg. the occipital lobe deals with visual information while the hippocampus in involved in encoding long term memories

behaviour can be explained by hormones

hormones ae chemical substances that affect target organs

they are slow acting in comparison to the nervous system but very powerful

eg. testosterone is linked to aggression in both genders, adrenaline causes a fight or flight response

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Selye's GAS Model (1936)

the body produces a general response to stress

the response enables the body to cope with stress

it is a syndrome as it is a condition that is defined by different identifiable symptoms

Stage 1: Alarm

the threat is recognised and the response is alrm

the hypothalamus triggers adrenaline production, and causes a fight or flight response

IN RATS; first 6 to 48 hours, a phsiological triad appears of enlarged adrenal glands, ulcers in the digestive system and shrinkage of the immune system

Stage 2: Resistance

this is the coping phase

resources are gradually depleted

things are deteriorating

IN RATS: if treatment continued the function of internal organs returned to normal

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GAS

Stage 3: Exhaustion

body can no longer remain normal function

the initial symptoms MAY reappear

the adrenal glands are damaged from prior over activity

coritsol production has slowed

stress related illness occurs such as depression and cardiovascual problems

IN RATS; after 1 to 3 months the animals lost resistance and displayed the symptoms from the original physiological triad. This is a 'doctrine of non specifity' as it occured in every stressor (noxious agents, excessive excercise, sublethal drugs, spinal shock)

Update

Resources are not depleted in the resistance phas, instead cortisol levels have a negative effect on the function of the immune system whihc is why it fails

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Psychosurgery

Link to Assumpions

mentally disordered behaviour has a physical, biological cause

the aim is to alleviate some of the servere symptoms of mental illness by destroying areas which cause abnormal behaviour

History

practiced by early humans are trephanning

in the 1930s, Egaz Moniz developed the prefrontal lobotomy (practiced in chimps at the time who demonstrated aggressive behaviour)

popularised by Freeman with the ice pick technique which simply severs connections and does not remove the lobes like in earlier methods

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Examples of psychosurgery

Prefrontal Lobotomy (leucotomy)

destruction of connections to the prefrontal cortex, this is involved with impulse control

hoped to alieviate distressing thoughts and behaviours

holes drilled into the sile of the skull and nerve fibres destroyed, later a leucotome was used

Comer (2002) 6% of patients show a range of severe side effects such as seizures and lack of emotional responsiveness

Deep Brain Stimulation

no tissue damage

wires placed in brain that are controled by a battery pack in the chest which produce a changeable high frequency current that interupt brain circuitry

Methodology: Brain Scanning

Links to Assumptions

the biological approach assumes that behaviour can be explained in terms of activity in the brain, if we see brain activity (seeing different lobes and hemispheres active under different tasks), we can predict behaviour

EEG (Electroencephalogram)

early scanning technique

electrodes are placed on the pbrain and sense electrical impulses

Derment and Kleitman (1957) used EEG to detect sleep stages, found we are most likely to remember a dream if woken in REM sleep

CAT (Computer Axial Tomography)

series of x rays that combine to form a two or three dimensional image

dye is injected as a contrast material

Useful as they show abnormal brain stricyires and are higher quality than x ray

require more radiation and so can not be used with pregnant women or repeated

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Brain Scanning

MRI scans (Magnetic Resonance Imaging)

using magnetic field to change the alignment of atoms and emit different radio signals

a dector reads this and turns it into a map of the brain

Maguire et al (2000) taxi drivers have enlarged hippocampi and this is an area associated with spacial awareness and direction